Sheet dryer of conveyor-wicket type with suction wickets



SHEET DRYER or CONVEYOR-WICKET TYPE WITH SUCTION WICKETS Filed Sept. 22.1961

R. R. SEEDO'RF July 6, 1965 3 Sheets-Sheet l INVENTOR.

w; ZZ Z? July 6, 1965 R. R. SEEDORF SHEET DRYER 0F CONVEYOR-WICKET TYPE WITH SUCTION WIOKE'IS Filed Sept. 22, 1961 5. Sheets-Sheet 2 July 6, 1965 R. R. sEDoRF 3,192,648

SHEET DRYER OF CONVEYOR WICKET TYPE WITH SUCTION WICKETS Filed Sept. 22.- 1961 3 Sheets-Sheet 3 United States Patent mamas sneer marina or CQNVEYGR-WIQKET rrrn' wrrn SU-CTHEN winners Robert R. Seedorr", Perl; Ridge, ilh, assigner to The Rey M. Mathis Company, a corporation of lliineis Filed Sept. 22, 195i, Ear. No. 140,5i52 4 Qlainrs. (Cl. 34-15%} This invention relates to a sheet handling and treating device and more particularly to a dryer utilizing the flow of air therethrough for holding sheets during conveying thereof through the dryer.

In the past it has been conventional in sheet dryers to provide a conveyor with wickets for supporting sheets travelling through the dryer. This practice has been satisfactory except when sheets are of limp material or of material which tend to curl with heat. Attempts have been made to satisfactorily handle sheets of this type by various mechanical gripping arrangements and other expedients; however, these have not proven satisfactory due to their complexity and damage to the sheets.

An object of this invention is to provide new and improved sheet handling structure for a sheet dryer or the like in which limp sheets or other sheets requiring support are supported without any mechanical gripping or other means causing damage thereto.

Another object of the invention is to provide sheet handling structure as defined in the preceding paragraph in which air fiow through a dryer is utilized to create a negative pressure which is used for support of the sheets.

A further object of the invention is to provide a sheet dryer having a casing with a central interior chamber through which sheets to be dried are passed, means for supplying air to the chamber, means for drawing air from the chamber, and conveying means for carrying the sheets through said chamber including members holding the sheets associated with the conveying means by negative pressure.

Another object of the invention is to provide a device for handling sheets in which a casing has a chamber through which sheets pass, means for drawing air from the chamber, and means for conveying and supporting sheets through the chamber including a plurality of suction wickets extending upwardly within the chamber and responsive to the flow of air from the chamber for holding sheets thereon in which the Wicket bases are constructed and arranged to create a velocity of air passing from the chamber suflicient to create a negative pressure which extends to holes in the wickets through the hollow I interior thereof to place the interior of said wickets at substantially the same negative pressure.

Further objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a vertical central section through a sheet dryer shown in association with a sheet delivering device and showing the ends of the dryer on the leftand right-hand sides thereof;

FIG. 2 is an enlarged vertical section taken generally along the line Z2 in FIG. 1;

FIG. 3 is a vertical fragmentary section on a further enlarged scale taken generally along the line 3-3 in FIG. 2; and

FIG. 4 is a fragmentary perspective view of a part of the wicket base and its association with the conveyor.

While this invention is susceptible of embodiments in many diiferent forms, there is shown in the drawings and will herein be described in detail an embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification f the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

First referring to FIG. 1, sheets arrive at a dryer indicated generally at it on a ribbon-type conveyor 11 which has received the sheets from a prior sheet treating device, such as a printer, and the sheets are individually supported on wickets, subsequently to be described, which pass upwardly with a somewhat clockwise pivoting movement as shown in FIG. 1. The sheet is then conveyed through the dryer and discharged onto a subsequent conveyor at the right-hand end of the dryer. Although it is not possible with all sheets, some sheets can have a return path of travel along the lower side of the dryer and are supported by the wickets.

The dryer 10 embodies a casing with a pair of spaced sidewalls 14 and 15 supported from the floor by a suitable leg structure, a pair of which are indicated at 16 and 17.

A plenum at the top of the casing is defined by a top cabinet wall 18 and a perforated bottom plate 19 spaced from the top wall 18 taken together with the sidewalls 14 and 15 and spaced end walls 19a and 19b. This plenum receives a supply of heated air through an inlet 2 1? which is supplied from'a blower 21 driven by a motor 22. The blower has an outlet connected by a vertically extending duct 23 to the plenum inlet 26. The inlet of the blower 121 communicates with a combustion chamber 24 having a burner 25 whereby the air to be delivered to the plenum chamber is heated to the desired temperature, prior to delivery. This blower, as an example, may be Model No. 600 BL with variable inlet vanes made by Buiialo Forge Co. and has adjustable vanes providing for the desired flow of air therethrough.

The casing sidewalls 14 and 15 define an elongate chamber beneath the plenum through which the wickets travel. Beneath the chamber is an open topped suction box 31 defined by a bottom wall 32 and the casing sidewalls 14 and 15 with end walls 33 and 34 formed as inclined extensions of the bottom wall 32 for a purpose described hereinafter.

The suction box, as stated, is open topped, except as effectively partially closed by parts of the wickets described subsequently.

Air is drawn from the chamber 30 into the suction box 31 by a blower 35 connected to a suction box outlet 36 by a duct 37. The blower 35 is driven by a motor 38 and preferably is of the same type as the blower 21 so the negative pressure can be controlled by changes in air flow quantity by adjusting blower inlet vanes. The path of air through the dryer has now been described and upon examining FIGURES 1 and 2 it will be noted that arrows showing the direction of air flow have been added thereto.

The conveying means for carrying sheets through the dryer embodies a pair of spaced apart link conveyor chains 40 and 41 with the upper reaches thereof supported on elongate angle bars 43 and 44, respectively, extending lengthwise of the chamber and secured to the sidewalls as shown in FIGS. 1 and 2. The angle bars 43 and 4-4 have suitable extensions outwardly of the ends of the casing as indicated at Ma and 4% whereby the chain is supported as the wickets change their angle relative to the vertical in approaching and leaving the dryer chamber.

The conveyor chains 40 and 41 are supported by a pair of sprockets at each end of the angle bars with the sprockets for the conveyor chain .31 being shown in FIG. 1. An idler sprocket 47 is at the outlet end and a drive sprocket 48 is at the other end. The drive sprocket is driven through a transmission connection 4? from the associated printer.

The lower reach of the conveyor is supported second set of elongate angle bars 50 and 51 dis 0 beneath the bottom of the suction box 31.

For support of the sheets such as sheets of limp film or other sheets that tend to curl with heat, a plurality of suction wickets are associated with the conveyor. These suction wickets are disposed one site the other and'each wicket comprises a wicket base ext a sed JJ transversely of the drying chamber and secured to the conveyor chains 4d and 41 by rivets 56 or the like fastened to a bracket 57 turned inwardlyfrom a chain link 58. These wicket bases extend the width of the chamber and each has an upturned flange 59 defining a central platform 63 on which an edge of a sheet may rest. A panel portion 61 of the wicket base extends downwardly at an angle to the wicket platform and has a strengthening flange 62. The base is provided with a series of openings 63 each receiving a wicket member 64 with the lower end of the wicket member secured to the panel 61 as by weldin Each of the wicket members are generally rectangular in cross section with a hollow interior and a series of holes 65 in the front leading face thereof which communicate with the/hollow interior of the wicket member. The wicket member has a closed upper end 65a and an open lower end 66 extending beneath the level of the wicket base platform.

With the wicket member, in the chamber, extending upwardly from the conveyor atan approximate angle of 40-45 degrees from the vertical, a sheet rests upon the wicket member 64 and has its lower edge confined on the platform of the wicket base.

As seen particularly in FIG. 3, the wickets are arranged with the wicket bases adjacent to each other. The flange 59 of one wicket base engages with the back side of the. preceding wicket members d4, there being a series, of wicket members associated with one wicket base and spaced apart transversely of the chamber, as seen in FIG. 2.

In order LO obtain adesired negative pressure in the area of the suction box and beneath the platforms of the wicket bases, the spacing between the adjacent wicket bases is designed accordingly. For example, if air is required to flow at 200 feet per minute to provide suf ficient air for drying, a desired negative pressure of approximately one inch would require that air should flow through the space between wicket bases at 4008 feet per minute. With this figure the total space required between the wicket bases in the chamber may be calculated and then the space between individual wicket bases. The foregoing is merely intended as an example and not as a limitation to the operation of the structure disclosed. Further, it should be noted that although FiG. 3 shows a wicket base flange & in contact with the backside of the preceding wicket member 64, there is actually a flow path since there are lengths of the wicket base 59 which do not contact wicket members due to the spaced transverse location of the wicket members.

The number of holes 65 formed along'the length of the elongate wicket members 64 may vary with the weight of sheet to be handled; however, having some holes uncovered is no problem since the blower can be adjusted to handle a greater rate of air fiow to obtain the desired negative pressure which must be done for initial loading when the dryer is empty. In operation, the negative pressure exists beneath the base platforms and generally the same pressure exists within the interior of the wicket members due to communication through the open ends 66 of the wicket member. Because of this, a sheet overlying the holes 65 will be held on the wicket.

Referring to P16. 1, the conveyor inclination varies at the inlet and outlet ends of the dryer and therefore the angle of the wicket members to the vertical also varies.

In order to hold a sheet on a wicket, by means of the negative pressure as the wicket starts to move from a horizontal position towards the inclined position for travel through the dryer, the suction box is extended by the bottom wall section 33, previously described. The sheet is held on an exiting wicket by the bottom wall extension 34 of the suction box. The side walls 14- and of the casing are also suitably extended. If necessary, a suitable rubber seal may be provided to prevent additional air flow around the edges of the wall sections 33 and 3 2, however, this flow normally can be taken care of by control of the exhaust blower 35.

Although it will not be done with limp sheets, it is possible to carry a sheet along the lower reach of the conveyor and each wicket is provided with a trailing shoulder which will support a sheet that has previously been held by the succeeding wicket. This sheet is received as the wickets start to travel toward the lower reach of the conveyor. I

I claim:

1. In a sheet dryer having a casing with an elongate tunnel chamber for drying sheets, a plenum with perforations opening to the chamber, means for directing heated air to the plenum, an open topped suction box beneath the chamber, means for drawing air from the chamber to the suction box for exhaust, an endless conveyor having one reach passing through the chambet, a plurality of wickets carried by said conveyor one after the other and each having a leading face and each including a wicket base secured to the conveyor to have the wickets in said reach and in the chamber extend at an angle from the vertical, each of said wickets having a hollow interior with holes along the length of the leading face thereof and an open end beneath the level of the wicket bases, means mounting the wicket bases in spaced relation on said conveyor with the spacing being of such magnitude to increase the velocity of air passing between the wicket bases, and means directing the air of increased velocity past the open ends of the wickets to create a negative pressure within the wickets which extends to the holes in the wickets to hold sheets thereon.

2. In a sheet dryer as defined in claim 1 in which the conveyor has inclined paths externally of each end of the chamber in which the wickets change their angle relative to thevertical, extensions of said suction box being associated with the wickets at said inclined conveyor paths for subjecting the latter wickets'to negative pressure.

3. In a sheet dryer having a casing with an elongate tunnel chamber for drying sheets, a plenum with holes opening to the cham er, means for directing heated air to the plenum, an open topped suction box beneath the chamber, means for drawing air from the chamber to the suc tion box for exhaust, an endless conveyor having one reach passing through the chamber, a plurality of wickets carried by said conveyor one after the other each includinga wicket base having a platform with an upturned flange defining a channel, a plurality of wicket members secured in spaced relation along the length of a wicket base transversely of the chamber and at a distance from the base channel whereby a sheet resting on the wicket member platform has its lower end confined by the channel, said wicket member being hollow and elongate with one or more holes therein along the length thereof adapted to be covered by a sheet of material being conveyed, said wicket members having an open lower end at a level beneath the platform whereby exposure of said ends to negative pressure places the interior of said wicket members at substantially the same pressure to hold a sheet without any mechanical holding, means mounting the wicket bases in spaced relation on said conveyor with the spacing being of such magnitude to increase the velocity of air passing between the wicket bases, and means directing the air of increased velocity past the open ends of the wicket members to create anegative pressure within the easaeas wicket members which extends to the holes in the Wicket members to hold sheets thereon.

4. In a dryer having a casing with an elongate tunnel chamber for drying a product, means for directing heated air to the chamber, an open-topped suction box beneath the chamber, means for drawing air from the chamber to the suction box for exhaust, a conveyor passing through the chamber, a plurality of wickets carried by said conveyor one after the other each including a wicket member and wicket base having a platform with an upturned flange defining a channel whereby a product resting on the platform has its lower end confined by the channel, said wicket members being hollow and elongate with one or more holes therein along the length thereof adapted to be covered by a product being conveyed, said Wicket members having an open lower end at a level beneath the platforms whereby exposure of said ends to negative pressure places the interior of said wicket members at substantially the same pressure to hold a product without any mechanical holding, means mounting the Wicket bases in spaced relation on said conveyor with the spacing being 6 of such magnitude to increase the velocity oi air passing between the wicket bases, and means directing the air of increased velocity past the open ends of the wicket members to create a negative pressure within the wicket members which extends to the holes in the Wicket members to hold products thereon.

References Cited by the Examiner UNITED STATES PATENTS 707,765 8/02 Elliot 34-150 1,399,415 12/21 Taliaferro 34-150 1,513,619 10/24 Luehrs 34-150 2,209,760 7/40 Berry 34115 2,668,366 2/54 Barnett 34150 2,899,926 8/59 Leibold 27172 FOREIGN PATENTS 1,194,331 11/59 France.

NORMAN YUDKOFF, Primary Examiner. 

1. IN A SHEET DRYER HAVING A CASING WITH AN ELONGATE TUNNEL CHAMBER FOR DRYING SHEETS, A PLENUM WITH PERFORATIONS OPENING TO THE CHAMBER, MEANS FOR DIRECTING HEATED AIR TO THE PLENUM, AN OPEN TOPPED SUCTION BOX BENEATH THE CHAMBER, MEANS FOR DRAWING AIR FROM THE CHAMBER TO THE SUCTION BOX FOR EXHAUST, AND ENDLESS CONVEYOR HAVING ONE REACH PASSING THROUGH THE CHAMBER, A PLURALITY OF WICKETS CARRIED BY SAID CONVEYOR ONE EACH INCLUDING A WICKET BASE SECURED TO THE CONVEYOR TO HAVE THE WICKETS IN SAID REACH AND IN THE CHAMBER EXTEND AT AN ANGLE FROM THE VERTICAL, ONE OF SAID WICKETS HAVING A HOLLOW INTERIOR WITH HOLES ALONG THE LENGTH OF THE ING A HOLLOW INTERIOR WITH HOLES ALONG THE LENGTH OF THE LEADING FACE THEREOF AND AN OPEN END BENEATH THE LEVEL OF THE WICKET BASES, MEANS MOUNTING THE WICKET BASES IN SPACED RELATION ON SAID CONVEYOR WITH THE SPACING BEING 